public class test {
    public static void main(String[] args) {


                long[] num = new long[10];
                num[0] = 9;
                long number = 0;
                for(int i = 1;i<10;i++){
                    num[i] = num[i - 1]*10 + 9;
                }
                for(int i = 0;i<10;i++){
                    number += num[i];
                }
                System.out.print(number);
                //write your code here........


    }
}

